US3478740A

US3478740A - Breathing apparatus with pressure reduction warning device

Info

Publication number: US3478740A
Application number: US600962A
Authority: US
Inventors: Karl Fredrik Wennberg
Original assignee: AGA AB
Current assignee: AGA AB
Priority date: 1965-12-23
Filing date: 1966-12-12
Publication date: 1969-11-18
Anticipated expiration: 1986-11-18
Also published as: DE1559609B1; GB1169908A; FR1505993A

Description

Nov. 18, 1969 K. F. WENNBERG 3,478,740

BREATHING APPARATUS WITH PRESURE REDUCTION WARNING DEVICE Filed Dec. 12, 1966 2 Sheets-Sheet 1 INVENTOR KARL F. WENNBERG ATTORNEYS Nbv. 18, 1969 K. F. WENNBERG 3,478,740

BREATHING APPARATUS WITH PRESURE REDUCTION WARNING DEVICE Filed Dec. 12, 1966 2 Sheets-Sheet 2 INVENTOR KARL F.' WENNBERG BY QQQ, Day/w ATTORNEYS United States Patent U.S. Cl. 128146.4 7 Claims ABSTRACT OF THE DISCLOSURE A breathing apparatus having a breathing mask, a pressure gas container, a conduit leading from the container with a pressure reducing device to the breathing mask, a high pressure valve connected in the conduit, and having a valve chamber with a valve member therein springbiased towards a valve seat communicating with the pressure gas source. The valve shaft carrying the valve memher is movable such that the opening between the valve member and the valve seat assumes a short and limited length so that the valve member will close when the pressure goes below a certain level.

The invention relates to a breathing apparatus having a breathing mask, a pressure gas container, a conduit leading from the container via a pressure reducing device to the breathing mask, and a high pressure valve connected in the conduit between the container and the pressure reducing device and having a valve chamber and, provided in the chamber, a valve member which is spring-biased against a valve seat communicating with the pressure gas source for shutting oil the gas supply.

An object of the invention is to warn the wearer of the *breathing apparatus when the pressure in the high pressure container has gone down to a certain level by causing blockage of the gas supply without forcing the wearer however to take any immediate step to make the supply operate again.

The invention is characterized by a valve shaft carrying the valve member and movable with certain play by the movement limiting arrangement, whereby the opening between the valve member and the valve seat only can assume a short and limited length which is fitted in that way that the valve member will close by getting below a predetermined gas pressure.

In comparison with prior known devices, the invention has the advantage referred to above consisting in that the wearer does not have immediately to take any steps when the gas supply is cut off, the supply being normally reopened when the container pressure acts on the valve and the opening pressure rises, It is therefore characteristic of the device that the reduced opening pressure present during gas consumption becomes insuflicient, when the container pressure has gone down under the said level, for keeping the valve opened, whereby a warning signal is given. However, when the container pressure is only slightly below the said level, there is an almost immediate return of the valve, so that the eifect of the warning on the wearer consists only in cutting off the latter part of his inhalation. Upon a continuation of the consumption of gas, the container pressure decreases more, and this can go on down to a lower value of the pressure, during which time however the gas output that is required to cause a warning to be emitted will be smaller and smaller. Finally, no gas output can be obtained at all, but the valve has to be opened by hand.

Preferably, the apparatus is provided with a catch and 3',4 78,740 Patented Nov. 18, 1969 with actuating means for opening the valve and locking the same in the opened position. It is particularly suitable to construct the actuating member in such a way as to be actuated by pulling, since this lessens the danger of unintentional actuation of the member by pushing or the like.

An embodiment of the invention is shown on the drawing, in which:

FIG. 1 is a schematic diagram of a breathing apparatus according to the invention;

FIG. 2 shows the high pressure valve with the warning device; and

FIG. 3 is a section on the line IIIIII of FIG. 2.

The FIG. 1, 1 is a breathing mask, 2 a breathing regulator having an exhalation valve and an inhalation valve controlled by the breathing pressure. The regulator 2 is supplied via a conduit 3 from a pressure regulator 4. The breathing regulator 2 and the pressure regulator 4 together form a pressure reducing device, to which gas is supplied from a pressure gas container 5 via a high pressure valve 6 with a warning device, which can be actuated by means of a handle 7.

FIG. 2 shows in detail the construction of the high pressure valve 6. It comprises a housing 11, the lower portion 12 of which has a recess into which a cylindrical valve chamber 13 is screwed, which is provided with an aperture for a valve shaft 14 at the upper end. Mounted on shaft 14 is a valve member 15, which in its lower position seats on a valve seat 16, which communicate via a conduit 17 with the pressure gas container 5. Around the valve seat 16 there is an aperture which connects with a conduit 18 leading to the pressure regulator 4, The valve member is actuated in the closing direction by a spring 19, the upper end of which rests on a washer 20. A washer 21 having a sealing ring inserted under it is in contact with the roof of the chamber, and the undersurface of the sealing ring has a recess 23.

The valve shaft 14 continues upwardly and is movable with play in an actuating sleeve 24. The play is due to a pin 25 mounted on the shaft which engages a hole 26 in the wall of the sleeve 24, which is provided with a lower widened portion 27 forming an upper and a lower shoulder. Resting on the upper shoulder is a sleeve 28, which causes a downwardly directed pressure on sleeve 24 by means of a spring 29.

In the lowermost position of sleeve 24 shown in the figure, the widened portion 27 is surrounded by a catch in the form of a locking disc 30 which in the uppermost position of sleeve 24 can engage the lower shoulder of the widened portion 27 and lock sleeve 24 in an upper position, in which valve member 15 is unseated from seat 16.

Sleeve 24 can be actuated by the pulling of a handle 7 connected to sleeve 24 by means of a flexible stem consisting of a steel wire 32, a spiral 33 and a cover 34 therefor.

FIG. 3 shows the locking disc 30 which is movable in its longitudinal direction and biased towards its outer locking position by a spring 35. In the free position shown, the widened portion 27 engages the wider portion of an aperture 36 provided in the locking disc. If the widened portion 27 is moved upwardly, so that the narrower portion of sleeve 24 below the same engages aperture 36, looking disc 39 is free to move outwardly under the influence of spring 35 to the locking position, in which the narrower portion of aperture 36 engages the narrower portion of sleeve 24 and the locking disc engages the undersurface of widened portion 27 and prevents the latter from being displaced downwardly.

OPERATION When the apparatus is in operation and no high pressure is present in conduit 17, the valve is in the position shown in FIG. 2. If the high pressure in conduit 17 is switched on, valve member 15 is pressed upwardly. Owing to the free movement of pin 25 in aperture 26, this can take place even when the actuating sleeve is in the lower position.

The opening pressure on the valve is then the container pressure obtained in conduit 17 from the pressure gas source when no gas consumption takes place. The opening force is predetermined by the container pressure on one hand and on the other hand by the area of the valve member on which the pressure acts.

When the valve member is unseated, it is influenced in the opening direction by an opening force which, if no gas consumption takes place, equals the product of the container pressure by the area on which it acts, this being in the embodiment shown in the cross section of shaft 14.

If gas consumption takes place however, the opening force is smaller and it then equals the product of the said area by the lower pressure then obtaining in conduit 17 owing the pressure drop which is present when gas is consumed. There is thus, on the one hand, a higher value of the opening pressure when no gas consumption takes place, on the other hand a reduced value during gas consumption. Between these two values there are obviously also a continuously decreasing series of intermediate values for the reduced pressure, these values being lower, the higher is the gas consumption.

The essential feature of the invention is the movement limiting arrangement of the valve member which, when the container pressure is doWn to a certain level, causes the reduced opening pressure to be insuflicient for keeping the valve open against the action of spring 19, whereby the valve closes and cuts off the gas supply. However, this exposes the valve to the container pressure, and as long as this has not gone too far down, it is sufiicient to re-open the valve. The length of the opening between the valve member and the valve seat is fitted in that way as to make even the most reduce'd opening pressure that can occur suflicient for keeping the valve open as long as the container pressure is above a certain level. A suitable value of this level may be 40 atrn. for a container having an initial pressure of 300 atm. When the container pressure is down below the said level, a very heavy reduction of the opening pressure is initially required to cause the valve to shut, and the wearer then only has to decrease his consumption slightly to make the opening pressure suffice for keeping the valve open. The more the pressure in the container goes down, the smaller is the reduction of the opening pressure relative to the container pressure that is required for the valve to close, and the consumption must be correspondingly low to prevent a shutoff from taking place. The wearer however can still go on with his occupation, but he does not have access to the same consumption of air as at a higher container pressure.

As the container pressure gradually approaches a certain lower level, at which not even this is sufiicient for opening the valve, the quantity of air that can be taken becomes gradually smaller. 1

The weare'r can make the warning device inoperative by pulling the handle 7. Actuating sleeve 24 is then moved to the upper position and locking disc 30 engages under the lower shoulder of widened portion 27 and retains the actuating sleeve in the upper position. Valve 15 is open and can not be closed, and the warning device is inoperative. It can be put in operation again by pushing in the locking disc 30 against the action of spring 35. Sleeve 24 is then released and the arrangement operates as described above.

What is claimed is:

1. A Warning device for a breathing'apparatus comprising a container for gas under pressure, a conduit leading from the container via a pressure reducing device to the breathing mask and a high pressure valve connected in the conduit between the container and the pressure reducing device, the high pressure valve having a valve chamber within which is provided a --valve member, means for spring biasing the valve member toward a valve seat to close the valve, a valve shaft connected to the side of the valve member opposite from the valve seat and having an area bigger than the area of the valve seat opening, and wherein said valve shaft is slidably mounted in an aperture in thechamber wall and extends through said chamber wall to a point exterior of said chamber.

2. A device according to claim 1 characterized in that the valve shaft is mounted to the chamber wall by a sealing ring and extends into an area open to the atmosphere surrounding the breathing apparatus.

3; Device according to claim 2 characterized in that a recess is formed in said sealing ring on the surface thereof turned towards the valve member.

4. Device according to claim 1, characterized by an actuating member mounted on the valve shaft for opening the valve by hand and comprising a sleeve which is movable in the direction of the valve shaft and engages the same with play.

5. Device according to claim 4, characterized in that the sleeve is spring urged towards the valve seat.

6. Device according to claim 4, characterized in that the actuating member comprises a handle connected with the sleeve by a flexible stem.

7. Device according to claim 4 characterized by a locking disc spring urged towards the locking position and adapted for locking the actuating member in the opening position.

References Cited UNITED STATES PATENTS 2,854,001 9/1958 Humblet 128142.2 3,028,860 4/1962 Gagnan et al. 128-142.2 3,147,761 9/1964 Lecocq 128-142.2

L. W. TRAPP, Primary Examiner